Cranberries are perfect for the holidays — but this sweet treat could be made with dried or glacéed cherries as well, and macadamia nuts or pecans could stand in for the pistachios.
Position a rack in the middle of the oven and preheat to 375 degrees F. Cut a 12x16-inch sheet of aluminum foil to line an 8-inch square baking pan, shiny side up. Let the edges of the foil overhang the pan. Generously butter the bottom and sides of the foil-lined pan with 1 tablespoon of the butter.
To make the crust, place 1 cup of the flour, 2 tablespoons of the sugar and the orange zest in the bowl of a food processor. Pulse to distribute. Add the remaining 5 tablespoons of butter and pulse on and off until the mixture is crumbly, with nibs of butter the size of peas. Transfer the mixture to the prepared pan and gently press the dough onto the bottom of the pan. Bake the crust until it turns pale golden, 10 to 15 minutes. Remove from the oven and allow the crust to cool completely while you make the filling.
To make the filling, place the egg in a small bowl and whisk to blend. Add the orange zest, agave syrup, and almond and vanilla extracts, and whisk to combine.
In another medium-size bowl, combine the salt, the remaining 2 tablespoons of flour and the remaining brown sugar. Add the egg mixture to the dry ingredients and stir to blend. Add the cranberries, pistachios and coconut, and stir to combine.
Spread the filling over the cooled crust in an even layer. Return the pan to the oven and bake until the filling is set and turns deeply golden, 20 to 30 minutes. Transfer the pan to a wire rack and let cool completely before cutting.
Lift the dessert from the pan by grasping the overhanging foil edges. With a sharp knife, cut into 12 bars. To store, arrange the bars in a single layer in an airtight container; they'll keep up to 5 days at room temperature.